Microwave-Assisted Spectroscopy of Vacancy-Related Spin Centers in Hexagonal Si C

Optically active spin centers associated with atomic scale defects in $\mathrm{Si}\mathrm{C}$ are promising candidates for quantum technology, owing to their outstanding optical and spin properties. Photoluminescence as a mature optical investigating tool is widely used for the identification of spin defects and exploration of their properties. However, in the case of spectrally overlapping contributions from different types of defects, traditional photoluminescence measurements cannot be used to separately obtain their optical and vibrational properties, such as the local phonon energy and the Debye-Waller factor. Here, we apply spin-resonant microwave-assisted spectroscopy to investigate the optical and vibrational properties of silicon vacancies in 6H-$\mathrm{Si}\mathrm{C}$ and divacancies in 4H- and 6H-$\mathrm{Si}\mathrm{C}$. We isolate contributions from each type of defect, investigate their local vibrational modes, and obtain the Debye-Waller factor. This work proves that microwave-assisted spectroscopy is a suitable tool for the investigation of optical and vibrational properties of a large variety of spin defects.